Embodiments of the present invention relate to vacuum process chamber components, for example, an electrostatic chuck for holding a substrate in a process chamber, and related methods of manufacture.
In the processing of substrates, such as semiconductor wafers and displays, the substrate is placed on a support in a vacuum process chamber and suitable processing conditions are maintained in the chamber. During processing, a process gas is introduced into the chamber and the chamber is typically maintained at low pressure or under vacuum conditions.
Components used in vacuum process chambers may be made from two different parts that are assembled together, either mechanically or by bonding the parts together. For example, an electrostatic chuck may comprise a composite baseplate and an electrostatic puck, which may both be made of similar materials such as metal or ceramics. In some instances, the baseplate may be made from metal and the electrostatic puck may be made from a ceramic material. Electrostatic chucks can be detachable and easily removed from a support pedestal for cleaning or replacement. The baseplate also has a good thermal conductivity to provide efficient removal of heat generated during processes which use plasma. It is generally difficult to join two parts made from dissimilar materials with an o-ring between the parts to form a hermetic seal. In situations where the materials have different coefficients of thermal expansion, conventional soldering and brazing techniques are undesirable because the coefficients of thermal expansion of the puck and baseplate are different. In conventional soldering processes, a large amount of the components adjacent the solder is heated and upon contraction small crack and stresses are formed. These stresses often occur when ceramic plates are bonded to metal plates. Therefore, there is a need in the art for bonding two parts together with an o-ring between the parts, for example, electrostatic chucks, that provide a good gas tight seal between the parts.